Method and arrangement for consolidating soil in a space to be consolidated

ABSTRACT

The invention relates to a method for consolidating soil in a space ( 10 ) to be consolidated. In the method, the consolidating agent is fed from a feeding container ( 9   b ) into the soil by mixing means ( 7 ) arranged in the consolidating agent feeding unit ( 4 ). The consolidating agent feeding unit ( 4 ) is positioned in connection with the transfer means ( 1 ) and the consolidating agent mixing means ( 7 ) arranged in the consolidating agent feeding unit ( 4 ) are moved by the transfer means ( 1 ) optionally at any point in the space ( 10 ) to be consolidated in the vertical direction (y), horizontal direction (x) and/or in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction and horizontal direction. The invention also relates to an arrangement for implementing the method.

The present invention relates to a method for consolidating soil in a space to be consolidated, in which method consolidating agent is fed from a feeding container into the soil by mixing means arranged in a consolidating agent feeding unit, the consolidating agent feeding unit is positioned in connection with transfer means, and the consolidating agent mixing means arranged in the consolidating agent feeding unit are moved by the transfer means optionally at any point in the space to be consolidated in the vertical direction, horizontal direction and/or in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction and horizontal direction.

The present invention further relates to an arrangement for consolidating soil in a space to be consolidated, the arrangement comprising a consolidating agent feeding unit, in which are arranged consolidating agent mixing means and a feeding container from which the consolidating agent can be fed into the soil by the mixing means, transfer means positioned in connection with the consolidating agent feeding unit, by means of which the consolidating agent mixing means fitted in the consolidating agent feeding unit can be optionally moved at any point in the space to be consolidated in the vertical direction, horizontal direction and/or in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction and horizontal direction.

Previously are known devices for consolidating soil which comprise a boom-like consolidating agent feeding unit. At one end of it are arranged consolidating agent mixing means known as such. The other end of the boom is typically connected to a reasonably easily movable boom which moves the bucket or the like of a heavy vehicle, such as a tractor or an excavator. It is reasonably easy to bring the excavator, and therefore the consolidating agent feeding unit, into the space to be consolidated or close to the soil to be processed otherwise. A device of this type is disclosed in the patent publication U.S. Pat. No. 4,652,180.

In the present context, the consolidation of soil refers, among other things, to the following procedures carried out on the soil: preparation of bearing slabs or the foundations of roads by mixing additives, such as cement and the chemicals required for hardening and stabilising the blended mass, into the soil; stabilisation, where additives are mixed into contaminated ground to harden the soil and to bind the contaminated particles in the ground stabilised in this manner.

A problem with this type of an arrangement is that the reach of the mixing means connected to an excavator or the like is limited and to a great extent determined by the range of reach of the excavator. Because of this, for example, stabilisation or other working of the soil can be carried out on a bearing base located next to the space being consolidated, which base carries the weight of the excavator. Thus, stabilising extensive overall spaces at the same time is impossible, which means that there may remain points of discontinuity in the soil to be stabilised, which may weaken the durability of the stabilisation. Points of discontinuity usually appear in a stabilisation space between two adjacent points stabilised at different times, whereby especially points of discontinuity on the vertical level may be formed between them.

A further problem with the previously known arrangement is that the consolidation of the soil, such as stabilisation, may remain incomplete. In other words, a part of the space may be left unstabilised, because when the mixing means are controlled by means of an excavator, a part of the space may be left unprocessed by the operator. For this purpose, the consolidating agent feeding unit (e.g. stabilisation unit) is now equipped with a positioning means, such as a GPS device, which gives position data on the basis of which the operator of a consolidating agent feeding unit will go through the stabilisation space using manual control. This requires a lot of experience and diversified knowledge of the operator in order to ensure that the consolidation is completely successful.

The aim of the present invention is to provide a method and arrangement by means of which the above disadvantages can be eliminated or substantially reduced.

In order to achieve the above-mentioned aims of the invention, the method according to the invention is characterised in that a supporting bridge included in the transfer means is positioned so as to extend across the space to be consolidated and in connection with the supporting bridge are positioned first transfer elements for moving the consolidating agent mixing means in a vertical direction and/or horizontal direction, and in the transfer means are positioned second transfer elements and the supporting bridge and the consolidating agent feeding means with mixing means are transferred by the second transfer elements in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction and horizontal direction.

Furthermore, in order to achieve the above aims of the invention, the arrangement for applying the method according to the invention is characterised in that the transfer means comprise a supporting bridge which is positioned so as to extend across the space to be consolidated, and first transfer elements arranged in connection with the supporting bridge for moving the consolidating agent mixing means in a vertical direction and/or horizontal direction, and second transfer elements arranged in connection with the supporting bridge for moving the supporting bridge and the consolidating agent mixing unit and the mixing means in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction and horizontal direction.

By means of the method and arrangement according to the invention is achieved an advantage with respect to the prior art in that the mixing means can be taken in a simple manner to each point in the space to be consolidated. Implementing the method and arrangement does not require any particular experience or special skills of the user, because control takes place entirely within the basic coordinate system, in which case the position coordinates of the consolidating agent mixing means are always known. Therefore, it is also positively known which point in the space to be consolidated has already been consolidated and which has not as yet been consolidated. Furthermore, the transfer means included in the method and arrangement according to the invention make possible so-called layer-by-layer consolidation, where the entire space to be consolidated can be stabilised in elevation/in the vertical direction one layer at a time. Vertical points of discontinuity are thus avoided.

Preferred embodiments of the present invention are disclosed in the dependent claims.

The invention is described in greater detail in the following, with reference to the appended drawings, in which:

FIG. 1 shows the transfer means according to the present invention for moving the stabilisation unit in the space to be stabilised, and

FIG. 2 shows an alternative arrangement applying the method according to the invention which differs from FIG. 1 only in that the supporting bridge 2 is not supported on the base by one end.

FIG. 1 thus shows an arrangement for applying the method. In this embodiment, the arrangement comprises a stabilisation unit provided in connection with the stabilisation space 10 (space to be consolidated), which is indicated by reference numeral 4 and the stabilisation unit's 4 transfer means indicated by reference numeral 1.

The stabilisation space is indicated by reference numeral 10. Here, the stabilisation space 10 is defined by firm soil 11 and 12, and in front of the space by firm soil, which is not shown here, and by the rear wall, which may also be firm soil. The spaces to be stabilised may also be adjacent to one another, such as 10, 10 b, and they may be separated from one another either naturally by harder or firmer soil or artificially by bearing material 11 brought to or made on site, for example, by cast-in-place concrete slabs or by concrete slabs brought to the site.

The stabilising agent (consolidating agent) is preferably supplied from a feeding container 9 b brought to the vicinity of the transfer means 1 via a feeder pipe 8 to the stabilisation agent mixing means 7.

The transfer means shown in FIG. 1 are described in greater detail in the following.

The transfer means preferably comprise a supporting bridge 2 extending across the stabilisation space 10, first transfer elements 3 arranged to move in connection with the supporting bridge and second transfer elements 5, by means of which the supporting bridge 2 may in turn be moved. The supporting bridge 2 is preferably supported by means of the second transfer elements 5 against the foundation soil 12 and, in the manner described above, against the bearing material 11 formed between the two stabilisation spaces 10 and 10 a.

The second transfer elements 5 are positioned in the lower part of the supporting bridge 2 and here they are arranged in both end areas of the supporting bridge 2, in this case one at either end. The supporting bridge 2 is furthermore preferably comprised of modules 2 a which can be joined longitudinally as extensions of one another. Thus, the length of the supporting bridge 2 and the distance A between the second transfer elements 5 can be adjusted to correspond to the longitudinal width of the stabilisation space 10 and the supporting bridge 2. The modules 2 a are also easy to transport to the site for assembly.

It should be mentioned that the second transfer elements 5 are preferably arranged to be movable or transferable with respect to the supporting bridge 2, for example, by means of guides (not shown) provided in the lower part of the supporting bridge 2. In that case, the arrangement of FIG. 2 can be applied, in which the supporting bridge 2 rests at one end by two transfer elements 5 on the foundation soil 11, whereby the other end of the supporting bridge 2, which is provided with stabilisation means 4 and transfer means 3 lies freely above the stabilisation space 10. The supported end of the supporting bridge 2 may be equipped with a counterweight (not shown), such as is known from crane booms, or it may be supported on a rail anchored to the ground.

A supporting bridge 2 may typically be made about 20-40 m long, but depending on the structure and use of the supporting bridge 2, the length may differ from this and be, for example, 15 m or 50-60 m. The second transfer elements 5 are preferably transfer cars which run on wheels, rolls and/or guides.

In connection with the supporting bridge 2 are arranged first transfer elements 3 for moving the stabilisation unit 4, and thus also the stabilisation agent mixing means 7, in the vertical direction and/or horizontal direction (horizontal direction refers here to the direction of the plane determined by the longitudinal direction of the supporting bridge, which may in practice deviate somewhat from the horizontal direction).

The second transfer elements comprise a transfer car 5. The transfer car 5 is arranged to move along the supporting bridge 2, across the stabilisation space 10 (this direction of movement is indicated by double-headed arrow x in the Figure). Also this transfer car 5 is preferably arranged to move on wheels, rolls and/or guides 6.

The stabilisation unit 4 is arranged in connection with the transfer car 5 belonging to the second transfer elements. The stabilisation unit 4 has an elongated body 4 a which is arranged to move into contact with the first transfer car 3 in the vertical direction, for example, on guides. This direction is indicated in the Figure by double-headed arrow y. Thus, the stabilising agent mixing means 7 are arranged to move by means of the first transfer elements 3 in the above-mentioned directions x and y (horizontally and vertically) and by means of the second transfer means 5 in a perpendicular or essentially perpendicular direction to the plane running through the said directions x and y (which is in a perpendicular or essentially perpendicular direction z to the plane of the paper). The mixing means 7 can be moved separately or simultaneously in each of the above-mentioned directions. It is, however, preferable that the horizontal transfer direction is the same as the transfer direction of the supporting bridge 2, whereby the horizontal transfer direction can be selected to remain essentially the same in different positions of the supporting bridge 2. Length B of the body 4 a of the stabilising unit 4 has been selected in such a way that the mixing means 7 at the lower end of the body 4 a can be taken to the desired depth with respect to the ground surface. Length B of the body is typically 2-12 metres which also essentially corresponds to the reach of the mixing means downwards in depth with respect to the ground level.

The stabilisation agent is fed from a feeding container 9 b arranged in a feeding carriage 9, which is preferably arranged on top of a movable car, such as a roller frame or a truck trailer 9 a or the like. The feeding takes place in a manner known as such with compressed air, which is generated by a compressor in the feeding carriage 9. The feeder pipe 8 is preferably arranged over a part of its longitudinal distance in connection with the transfer means 1, in this case in connection with the supporting bridge 2 included in the transfer means 1.

One advantage of the method and arrangement of the invention is that the mixing means are free to process the material handled by the transfer means 1 at any point in the stabilisation space 10 and the area being processed is not dependent on the progressing of the processing, such as stabilisation, from the edge of the space 10, as was the case earlier. This inventive feature may be applied, for example, by stabilising the space 10 by means of the so-called layer-by-layer method, in which the stabilisation of the stabilisation space can be carried out in layers, one layer at a time, whereby no vertical points of discontinuity are formed. In the Figures, these layers are indicated by reference marks a, b, c and d.

By means of the invention is also achieved accurate pillar stabilisation. In pillar stabilisation, the space to be consolidated is a group of spaces to be consolidated having predetermined locations, each of them requiring only a vertical movement, but between which are required precisely dimensioned movements in the horizontal coordinate system. If necessary, the mixing tools can be changed to suit pillar stabilisation.

The system may be automated so as to allow unmanned operation of the equipment. For example, mirrors are mounted at both ends of the bridge 2 and control is carried out by known PLC control, which receives control data by means of ranging and a laser by utilising the said mirrors.

The present invention is not limited only to the described embodiments, but it may be applied in many ways within the scope of protection defined in the appended claims. Although in the examples the method and arrangement have been applied to the stabilisation of soil, the invention is not limited to this, but concerns the consolidation of a space to be consolidated in general. 

1. A method for consolidating soil in a space to be consolidated (10), in which method consolidating agent is fed from a feeding container (9 b) into the soil by mixing means (7) arranged in a consolidating agent feeding unit (4), the consolidating agent feeding unit (4) is positioned in connection with the transfer means (1) and the consolidating agent mixing means (7) arranged in the consolidating agent feeding unit (4) are moved by the transfer means (1) optionally at any point in the space (10) to be consolidated in the vertical direction (y), horizontal direction (x) and/or in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction and horizontal direction, characterised in that a supporting bridge (2) included in the transfer means (1) is positioned so as to extend across the space (10) to be consolidated and in connection with the supporting bridge are positioned first transfer elements (3) for moving the consolidating agent mixing means (7) in a vertical direction (y) and/or horizontal direction (x), and in the transfer means (1) are positioned second transfer elements (5) and the supporting bridge (2) and consolidating agent feeding means (4) with mixing means (7) are transferred by the second transfer elements (5) in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction (y) and horizontal direction (x), and providing both ends of the supporting bridge (2) with the second transfer means (5), for supporting the supporting bridge (2) against the bearing material (11) and/or the foundation soil (12) where by the distance (A) between the second transfer means (5) is adjusted to correspond to the width of the space (10) to be consolidated in longitudinal direction of the supporting bridge (2).
 2. A method as claimed in claim 1, characterised in that the horizontal transfer direction (x) is the same as the longitudinal direction of the supporting bridge (2), and that the horizontal transfer direction (x) remains essentially the same in the different positions of the supporting bridge (2).
 3. A method as claimed in claim 1, characterised in that the first and/or second transfer elements (3, 5) comprise a transfer car or transfer cars which run on wheels, rolls and/or guides (6).
 4. A method as claimed in claim 1, characterised in that between the feeding container (9 b) and the mixing means (7) is positioned an elongated consolidating agent feeder pipe (8) which is in connection with the transfer means (1) over a part of its longitudinal distance.
 5. An arrangement for consolidating soil in a space (10) to be consolidated, the arrangement comprising a consolidating agent feeding unit (4), in which are arranged consolidating agent mixing means (7) and a feeding container (9 b) from which the consolidating agent can be fed into the soil by the mixing means (7), transfer means (1) positioned in connection with the consolidating agent feeding unit (4), by means of which the consolidating agent mixing means (7) fitted in the consolidating agent feeding unit (4) can be optionally moved at any point in the space (10) to be consolidated in the vertical direction (y), horizontal direction (x) and/or in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction (y) and horizontal direction (x), characterised in that the transfer means (1) comprise a supporting bridge (2) which is positioned so as to extend across the space (10) to be consolidated, and first transfer elements (3) arranged in connection with the supporting bridge (2) for moving the consolidating agent mixing means (7) in a vertical direction (y) and/or horizontal direction (x), and second transfer elements (5) arranged in connection with the supporting bridge (2) for moving the supporting bridge (2) and the consolidating agent mixing unit (4) and the mixing means (7) in a perpendicular or essentially perpendicular direction to the plane running through the said vertical direction (y) and horizontal direction (x), and both ends of the supporting bridge (2) are provided with second transfer means (5), for supporting the supporting bridge (2) against the bearing material (11) and/or the foundation soil (12) where by the distance (A) between the second transfer means (5) is adjusted to correspond to the width of the space (10) to be consolidated in longitudinal direction of the supporting bridge (2).
 6. An arrangement as claimed in claim 5, characterised in that the horizontal transfer direction (x) is arranged by means of the first transfer elements (3) to be the same as the longitudinal direction of the supporting bridge (2), and that the horizontal transfer direction (x) is arranged to remain the same in the different positions of the supporting bridge (2).
 7. An arrangement as claimed in claim 5, characterised in that the first and/or second transfer elements (3, 5) comprise a transfer car or transfer cars which run on wheels, rolls and/or guides (6).
 8. An arrangement as claimed in claim 5, characterised in that between the feeding container (9 b) and the mixing means (7) is positioned an elongated consolidating agent feeder pipe (8) which is in connection with the transfer means (1) over a part of its longitudinal distance.
 9. An arrangement as claimed in claim 5, characterised in that feeding container (9 b) is in a separate movable carriage (9) with means for pressurising air for feeding the consolidating agent by means of compressed air. 